// Copyright 2006 - Ricardo Stuven (rstuven@gmail.com)
//
// This file is part of MsSqlSpatial.
// MsSqlSpatial is free software; you can redistribute it and/or modify
// it under the terms of the GNU Lesser General Public License as published by
// the Free Software Foundation; either version 2 of the License, or
// (at your option) any later version.
// 
// MsSqlSpatial is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU Lesser General Public License for more details.

// You should have received a copy of the GNU Lesser General Public License
// along with MsSqlSpatial; if not, write to the Free Software
// Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA 

using System;
using System.Collections;
using System.Collections.Generic;
using System.Data;
using System.Data.SqlClient;
using System.Data.SqlTypes;
using Microsoft.SqlServer.Server;
using MsSqlSpatial;
using GisSharpBlog.NetTopologySuite.Geometries;
using GeoAPI.Geometries;

public partial class UserDefinedFunctions
{
	/// <summary>
	/// 
	/// </summary>
	/// <param name="table_name"></param>
	/// <param name="column_name"></param>
	/// <returns></returns>
	/// <example>
	/// </example>
	[SqlFunction(IsDeterministic = false, DataAccess = DataAccessKind.Read)]
	public static SqlBytes EnvelopeQuery(
		SqlString table_name,
		SqlString column_name)
	{
		return EnvelopeQueryWhere(table_name, column_name, SqlString.Null);
	}

	[SqlFunction(IsDeterministic = false, DataAccess = DataAccessKind.Read)]
	public static SqlBytes EnvelopeQueryWhere(
		SqlString table_name,
		SqlString column_name,
		SqlString condition)
	{

		using (SqlConnection connection = DatabaseHelper.ContextConnection)
		{
			connection.Open();
			using (SqlCommand command = connection.CreateCommand())
			{
				string tableName = table_name.Value;
				string columnName = column_name.Value;
				string schemaName = "";

				DatabaseHelper.SplitSchemaAndTableName(command, ref tableName, ref schemaName);
				int srid = GeometryColumnsTable.GetSRID(command, schemaName, tableName, columnName);

				string filterQuery = "";
				if (!condition.IsNull && condition.Value.Trim().Length != 0)
					filterQuery = "WHERE " + condition.Value;

				DatabaseHelper.BuildCommand(command, string.Format(
@"SELECT 
  Min([{2}_Envelope_MinX])
, Max([{2}_Envelope_MaxX])
, Min([{2}_Envelope_MinY])
, Max([{2}_Envelope_MaxY])
FROM [{0}].[{1}]
{3}
"
, schemaName			// {0}
, tableName				// {1}
, columnName			// {2}
, filterQuery			// {3}
));
				using (SqlDataReader reader = command.ExecuteReader())
				{
					if (reader.Read())
					{
						if (reader.IsDBNull(0))
						{		
							return SqlBytes.Null;
						}
						else
						{
							IGeometry envelope = GeometryFactory.Default.ToGeometry(
								new Envelope(
								  reader.GetDouble(0)
								, reader.GetDouble(1)
								, reader.GetDouble(2)
								, reader.GetDouble(3)
								));
							return ConvertGeometry.ToSqlBytes(envelope, srid);
						}
					}
				}
			}
		}

		return SqlBytes.Null;
	}

};

